In this question, I posted an answer which suggested that in some contexts, such as America today, man does not need to eat animals to survive, it is totally optional for us today. As a matter of nutrition, everything we need to survive is both available and abundant in other sources. Given this fact, how does Objectivism justify eating animals as moral? Granted, animals do not have rights (a concept pertaining to man), but can we justify eating them on the grounds that it is required for our survival - the standard of Objectivst morality.

Furthermore, one can make a good argument that animals are a rational value to humans, in ways other than as food.

Eating animals is moral because they are animals and a good potential food source. There is no other justification required.

Moreover, food is required for survival, but enjoyable, nutritious foods are required for health and happiness. Animals are the best and sometimes only source of ALL of the essential nutrients humans require for highest health. This is a plain fact.

To the extent that an animal is a value to humans for anything other than food, then humans ought to treat them that way. But because cats are awesome and run the Internet, does not mean cattle cannot be food.

The place to start here is by reviewing what it means for something to be moral. According to Objectivism, the moral is that which is good for man's life, and it is moral for a man to act is his best interest. Relative to animals, that means he should consider them with all his values in mind: as food (cows, chickens, ...), as a pet (goldfish, hamsters, ...), as laborers (horses, oxen, ...) and likely many other things as well, including a general benevolence as fellow living beings. To be moral, a man should consider his actions relative to any specific animal according to the animal's potential value to him along all of those criteria. For example, a dog makes for an excellent companion, and a good worker (even a highly trained worker). However, dogs are generally not considered very highly for eating. Thus, most men find keeping a dog as a pet to be in their best interest. With cows, some men find it better to feed, house, and defend them for their milk, and some find it better to slaughter them for their meat. The latter is completely rational (i.e., moral) choice if that man's interest is better served by eating the cow rather than preserving it.

The only grounds I could see for advocating that eating animals is immoral is that there is some value in holding benevolence toward other living creatures. However, I personally don't think it's immoral to hold eating animals as a higher value. However, because of that same value, I would hold that the wanton torture and slaughter of animals for no purpose whatever certainly would be.